[OpenLayers-Dev] On the relationship between ka-Map and OpenLayers
crschmidt at metacarta.com
Wed Apr 8 20:39:30 EDT 2009
For several years, thre has been an outstanding ticket in OpenLayers,
http://trac.openlayers.org/ticket/327 , which I have meant to spend some
on to help explain why I don't feel that the fixes in question are
appropriate for OpenLayers, and what I hope that users who are
interested in the ticket will do.
ka-Map provides two core pieces of functionality: a web-mapping API
similar to OpenLayers, and a PHP-based tile caching engine similar to
TileCache. In OpenLayers, we have ka-Map layers that support the use of
existing ka-Map tile setups using the PHP scripts of the ka-Map project.
Included in the OpenLayers 'examples' directory is a simple ka-Map
"like" example kamap.txt file. This file was a combination of a couple
different ka-Map files -- config.php and tile.php -- designed to be
primarily for people 'getting started' with ka-Map, not for long term
Any changes in the PHP code, I believe, belong within the ka-Map
project. The kamap.txt example file should probably be *removed* from
OpenLayers; it's misleading to include it there.
If there are changes neccesary in the *client* side code, I'm perfectly
willing to support them. The ka-Map changes suggested thus far have all
been entirely in the ka-Map PHP code, so far as I've seen -- with the
exception of a small change at the bottom of
which can be easily overriden by correctly configured clients, I
http://trac.openlayers.org/attachment/ticket/327/KaMap.patch is actually
the same patch, I believe.
Now, this particular change isnt' clear to me why it's needed, because
you can override 'i' in your client side code. However, the rest of the
changes -- splitting kamap.txt back up, etc. -- I believe these belong
in the ka-Map Project.
I'd love to see more effort put towards maintaining the ka-Map server
side code -- and maybe, if the project is interested, even supporting it
as a sort of 'mapserver tilecache for php' library. I'd be happy to have
the project share some mental space with tilecache towards that end, if
Looking at the ticket description, "Except - if the image type is PNG in
config.php, and GIF in the layer constructor, and the layer is not a
base layer, the GIF is created with a white background color, instead of
a transparent background color." is the client side problem.
This seems like a clientside misconfiguration to me, and I don't see how
making things not use default parameters helps.
With that in mind, it is my opinion that:
* #327 is probably a combination of server-side bugginess and
* The former should not be fixed in OpenLayers, and kamap.txt should be
removed from OpenLayers.
* The latter should be fixed by not misconfiguring the client.
For now, I'm going to bump this to 2.9; if we haven't heard anything new
in the near future, I'm likely to simply close it.
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